This invention relates to new adhesivizing agents for organic binding agents. This invention particularly relates to new nitrogen group containing silanes and their use as adhesivizing agents for organic binding agents employed to bond inorganic oxidic or metallic substances together. This invention relates to such adhesivizing compositions,
2. DISCUSSION OF THE PRIOR ART
Condensation resins of the phenolformaldehyde and amine resin type have long been used as binding agents for industrial purposes, in foundry operation, for example. They are used both in the form of aqueous solutions and in liquid form, or dissolved in organic solvents.
It has now been found that these binding agents have deficient binding characteristics when the bonded materials are exposed to moisture, as they are, for example, in the case of foundry cores and molds. It has been found that the mechanical strength of the bonded materials is lowered after they have been stored under moist conditions.
It has heretofore been proposed to solve this problem by the addition of .gamma.-aminopropyltriethoxysilane and related silanes. This silane is added to the resin component. The addition of such an organofunctional silane has proven useful in improving the bonding characteristics of organofunctional resins under moist conditions, particularly in improving the bonding characteristics of adhesives containing furan resins. Experience, however, has shown that the initial positive effect obtained by the addition of the silane is diminshed after the resinous bonding composition containing silane has been in contact with moisture for a long period of time. In fact, the addition of the aminosilane is inoperative in respect of a number of resins other than furan resins after relatively long storage time, for example, in phenolic resins or epoxy resins. This is probably to be attributed to a reaction between the silane and the resin component itself.
It, therefore, has become desirable to improve the bonding characteristics of polyaddition or polycondensation resinous-containing binding materials so that they have improved bonding characteristics under moist conditions and attain their bonding characteristics even after long storage times. It has become particularly desirable to provide an improved binding composition which has an excellent storage life and retains its ability to improve the bonding characteristics of polyaddition or polycondensation resinous binders. It has become particularly desirable to provide such an improved binder containing a silane.